Geochemistry and geotectonic setting of Late Proterozoic Katangan basic rocks from Kibambale in central Shaba (Zaire)

Abstract

The Late Proterozoic Katangan basic rocks (dolerites and basalts) outcropping at Kibambale in central Shaba (Zaire) are classified as extension-related tholeiites. The concentrations of immobile major and trace elements resemble those encountered in Phanerozoic enriched oceanic ridge basalts (E-MORB) emplaced in incipient oceanic rifts such as Red Sea and Tadjura Gulf troughs. This conclusion is also sustained by: elemental ratios which are MORB-like; multielement chondrite-and MORB-normalized patterns; sedimentological data, especially the shallow water conditions which prevailed during the deposition of lower Kundelungu tillite in which these basic rocks are interstratified; and the geological and structural framework, notably the emplacement of these igneous rocks in a basin not distant from the Kibaran continental land mass.In this area the geological units containing the igneous rocks are not affected by significant tangential tectonism and so the present structural relationships are relatively undisturbed compared with those which prevailed during the emplacement of the igneous rocks.

Geochemical characterisation, provenance, source and depositional environment of ‘Roches Argilo-Talqueuses’ (RAT) and Mines Subgroups sedimentary rocks in the Neoproterozoic Katangan Belt (Congo): Lithostratigraphic implications

“…The Grand Conglomérat and Roan Group sedimentary units pre-date the Lufilian orogeny. Mafic igneous rocks from Roan and Grand Conglomérat have geochemical features of magmas emplaced in East-African-type and Rea-Sea-type rift systems, respectively (Manteka et al, 1985;Kampunzu et al, 1991Kampunzu et al, , 1993Kampunzu et al, , 2000Tembo et al, 1999). The sedimentary succession of the Roan Group includes a conglomerate-sandstone-siltstone-shale and carbonate association, taken for a rift sequence by several authors (Raybould, 1978;Buffard, 1988;Cailteux, 1994).…”

The Mesoproterozoic Irumide belt of Zambia

“…Regional correlations Shackleton (1973) and Hanson et al (1988) suggested that the Irumide belt and the Choma-Kalomo block were two segments of the same belt cross-cut by the Neoproterozoic Zambezi belt. Kampunzu et al (1991Kampunzu et al ( , 1993Kampunzu et al ( , 2000 showed that igneous rocks exposed in the adjacent Damaran-Katangan segments of the Pan African orogenic system represent continental rift and Red-Sea-type mafic rocks, supporting limited development of Neoproterozoic seafloor along this trend, and therefore allowing the possibility of a linkage between the Irumide belt and Choma-Kalomo block. However, based on the presence of yoderite-bearing whiteschists in the Zambezi belt, Johnson and Oliver (2000) argue for the closure of a major Neoproterozoic ocean during convergence between the Congo and Kalahari cratons.…”

Genesis of sediment-hosted stratiform copper–cobalt deposits, central African Copperbelt

“…The Roan Group is made up of siliciclastic and carbonate sedimentary rocks (fluviatile and lacustrine sediments; Buffard, 1988;Cailteux et al, 1994), and volcanic and plutonic mafic rocks emplaced in a continental rift (Kampunzu et al, 2000 and references therein). The Nguba supracrustal assemblage is made up of siliciclastic and carbonate sedimentary rocks (François, 1974;Buffard, 1988) and includes mafic igneous rocks emplaced in a proto-oceanic rift similar to the Red Sea (Kampunzu et al, 1991(Kampunzu et al, , 1993Manteka et al, 1985;Kapenda et al, 1998). Kundelungu sedimentary rocks represent syn-to post-orogenic sedimentary deposits (Kampunzu and Cailteux, 1999).…”